A supposedly fun concert will turn into a crime scene in the next episode of "Chicago P.D." season 4.

According to the synopsis from The Futon Critic for the episode titled "Big Friends Big Enemies," a shooting incident that happened during a concert will lead to a wide-scale gang-related violence in the city. Good thing Lindsay (Sophia Bush) and Ruzek (Patrick John Flueger) are just around the area to control the scene.

The synopsis for the episode reads: "When a car plows through a crowd of concert goers and gunfire erupts, Lindsay and Ruzek are on the scene. Unsure of the motive and concerned a terrorist group may be responsible, Voight (Jason Beghe) orders in Homeland security, customs and the F.B.I. to assist. At the same time, Burgess (Marina Squerciati) spots Atwater's (LaRoyce Hawkins) brother, Jordan (guest star Ahmad Nicholas Ferguson), out where he shouldn't be. The team use their connections to throughout the city to bring some peace to the community before more blood is shed."

The fourth episode of "Chicago P.D." season 4 airs on NBC on Wednesday, Oct. 12.

Meanwhile, Senior Detective Antonio Dawson (Jon Seda) will be all over the "Chicago" franchise this season.

In an interview with TVLine, Seda revealed that his transition to the franchise's legal drama, "Chicago Justice," does not mean that he will no longer see his colleagues at the police department in the future. In fact, he will be seen visiting the firefighters of "Chicago Fire" as well.

"He'll be crossing over. It's really going to be seamless," the actor said about his character. He added that he is shooting the episodes in all the three "Chicago" franchises at the same time.

Seda also revealed that he will still be present in all of the first eight episodes of "Chicago P.D." season 4 before Dawson works full time in the State's Attorney's office in the first season of "Chicago Justice."